fix: add render_date() method for grids

and corresponding built-in for set_renderer()

tests/grids/test_base.py

@@ -213,7 +213,7 @@ class TestGrid(WebTestCase):
         obj = MagicMock(foo=42.00)
         self.assertEqual(grid.renderers['foo'](obj, 'foo', 42.00), '42')
 
-    def test_set_default_renderer(self):
+    def test_set_default_renderers(self):
         model = self.app.model
 
         # no defaults for "plain" schema
@@ -249,6 +249,18 @@ class TestGrid(WebTestCase):
         self.assertIn('executing', grid.renderers)
         self.assertIs(grid.renderers['executing'], myrender)
 
+        # nb. as of writing we have no Date columns in default schema,
+        # so must invent one to test that type
+        class SomeFoolery(model.Base):
+            __tablename__ = 'somefoolery'
+            id = sa.Column(sa.Integer(), primary_key=True)
+            created = sa.Column(sa.Date())
+
+        # renderer set for date mapped field
+        grid = self.make_grid(model_class=SomeFoolery)
+        self.assertIn('created', grid.renderers)
+        self.assertIsNot(grid.renderers['created'], myrender)
+
     def test_linked_columns(self):
         grid = self.make_grid(columns=['foo', 'bar'])
         self.assertEqual(grid.linked_columns, [])
@@ -1415,6 +1427,20 @@ class TestGrid(WebTestCase):
         # zero is *not* empty string (with this renderer)
         self.assertEqual(grid.render_quantity(obj, 'foo', 0), "0")
 
+    def test_render_date(self):
+        grid = self.make_grid(columns=['foo', 'bar'])
+
+        # null
+        obj = MagicMock(dt=None)
+        result = grid.render_date(obj, 'dt', None)
+        self.assertIsNone(result)
+
+        # typical
+        dt = datetime.date(2025, 1, 13)
+        obj = MagicMock(dt=dt)
+        result = grid.render_date(obj, 'dt', str(dt))
+        self.assertEqual(result, '2025-01-13')
+
     def test_render_datetime(self):
         grid = self.make_grid(columns=['foo', 'bar'])